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The average age of 30 students and the class teacher is20 years. I f the class teacher's age is excluded; the average reduces by 1 year. What is the age of the class teacher? |
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Answer» Step-by-step explanation: Let the age of teacher = t Sum of the ages of 20 students = S Given that, the average age of 20 students and the teacher is 16 years. (S+t) /21 = 16 ———-(1) Also given that, when the teacher is excluded then the average age is DECREASED by 1 year. S/20 = 15 ———-(2) From (2), S = 15x20 = 300 Substitute in (1), (300+t) /21 = 16 300+t = 336 t=36 Ans: Age of the teacher is 36 years |
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